1 / 49

CMS China Group

Explore Chinese contributions to CMS, including Higgs searching, J/ψ cross-section measurements, B physics studies, and software development. Detailed analysis of physics phenomena and experimental results.

petermcdonald
Download Presentation

CMS China Group

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CMS China Group Yajun Mao (Peking University) On Behalf of CMS China Group LHEP2010, Naning

  2. Outline Introduction of CMS China Group Physics Topics of Our Group Our plan for CMS upgrade Summary LHEP2010, Naning

  3. CMS Chinese Group IHEP: CSC, physics analysis Hesheng Chen, Guoming Chen, Cunhua Jiang Ming Yang, Zhen Wang, Jianguo Bian + 2-3post-doc + 10 students PKU: RPC, physics analysis Yajun Mao, Yong Ban, Sijin Qian，Siguang Wang + 10 students M&O members: 3 from PKU + 5 from IHEP LHEP2010, Naning

  4. IHEP: 1/3 Muon Detector ( CSC ) IHEP: Support for magnet, floor PKU: 1/3 mID detector (RPC) China Contribution to CMS Chinese Contribution: 5M CHF 25M (3.67+21.33M) RMB LHEP2010, Naning

  5. RPC From PKU (part) Mass production, installation-2006.2.13. 264 panels，2000m2, 3.72M RMB LHEP2010, Naning

  6. On Going Work of China Group B physics Higgssearching Other topics than B Physics and Higgs Software Work LHEP2010, Naning

  7. B physics • J/， cross section measurement • (2S)J/π+π- J/μ+μ- • B+ →J/K+ cross section measurement LHEP2010, Naning

  8. COM CSM J/Y截面：PRL, 79 (1997) 572 Test NRQCD @CMS 通过对LHC上pp对撞中大横动量区域来自直接过程的重味夸克素产物(J/y, y’, )的截面及极化的测量，分析NRQCD色单态模型与色八重态机制的贡献，研究重味夸克素产物的产生机制。挖掘相关现象背后的物理规律。 J/Y极化：PRL, 85 (2000) 2886 LHEP2010, Naning

  9. J/ψμ+μ- cross section Crystal Ball J/ψ Exp function Ψ(2S) Υ(nS) Z Left: the CMS dimuon mass spectrum. Right: global muon pairs in difference rapidity bins, corresponding to the CMS barrel, endcap and transition part. LHEP2010, Naning

  10. Acceptance and Efficiency Left: Acceptance as a function of pT and rapidity of the J/ψ. Right: distribution of the pT and |y| in data of the muon pairs within ± 100 MeV/c2from the nominal J/ψ mass. LHEP2010, Naning

  11. Prompt and nonprompt J/y cross section Distribution of prompt J/ψ (left)and nonprompt J/ψ (right) cross section in both CMS measurement and theory for |y| < 2.4. LHEP2010, Naning

  12. (2S)J/π+π- J/μ+μ- Prompt: B decay: Similar analyzing method and mass window as X(3872) Fusibility study completed, start real data analysis LHEP2010, Naning

  13. B+ →J/K+ Production B+mass spectrum Real data MCresult B+的寿命 MC study completed, real data study on going, ，result is expected to be published mid next year LHEP2010, Naning

  14. Higgssearching • H • qqH，HWW l l  • Same sign WW scatteringW as a probe of Higgs LHEP2010, Naning

  15. H and Related Study Very important Higgs discovery channel, a lot work are done as following Converted /0 identification Unconverted /0 identification Dead crystal energy recovery H Cross section and branch ratio calculation at 7,10TeV High energy  calibration with Z  channel isolation study Gluon fusion Higgsdiscovery protencil study Vector boson fusion Higgsdiscovery protncil study  energy calibration with 0 channel LHEP2010, Naning

  16.  Energy Calibration with 0 Data MC 0γγ 0γγ mass resolution 8.1% mass resolution 7.4% scale uncertainty at level of 1% LHEP2010, Naning

  17. Difference from the other study p0 利用AMS束流测试中得到的簇射形状经验公式 对CMS电磁量能器的簇射叠加进行拆分 大幅度提高了H→的灵敏度 当higgs质量为 120GeV，CMS 最多需要16/fb 来 发现它。原先估计 是50/fb IHEP PTDR LHEP2010, Naning

  18. H searching Expected at 10/fb 当higgs质量为120GeV，CMS最多需要16/fb 来发现它 （14TeV） LHEP2010, Naning

  19. VBF HiggsWWlnln study A SM Higgs production process with 2nd largest cross section at LHC Important for disentangling Higgs couplings In fermiophobic Higgs models, it can be the only production mechanism for such a Higgs at LHC Significant signature of two energetic jets with large rapidity gap Little gluon radiation in the central-rapidity region Sensitive region from mH 140GeV-200GeV for HWW channel LHEP2010, Naning

  20. Discovery potential(1fb-1@7TeV) • Counting Experiment, 1 sigma result achieved for mH 160-180GeV • Large jet uncertainty, total systematic error is about 60% • Not a discovery channel, but important contribution • Comparing with 10TeV, the result is reasonable: • NLO cross section, gain 30% more signal • new jet algorithm and correction • Better b-tagging performance • ggH influence are considered LHEP2010, Naning

  21. Jet study in a VBF point of view Single Jet distributions Mjj (GeV) Δη Di-Jet distributions pT (GeV) η MC are normalized to the same integrated luminosity of data Ak5 jet, L2L3 correction, pure09 loose JetID pT 1st and pT 2nd jet spectrums Central region jet pT>25GeV, Forward region jet pT>30GeV MC seems describe QCD di-jet distributions well LHEP2010, Naning

  22. Same Sign WW Scattering(Wμν) • Scattering amplitude grows in absence of the Higgs particle • Different topology for Higgs absence(B+C) and Higgs existence(A+B+C) scenario • Very clean channel, two same sign muons and two energetic forward jets A B C + 60fb-1 at 10TeV LHEP2010, Naning

  23. Other topics • pp→ppXexclusive process • ttbar cross section measurement • Forward Central Jet associate production LHEP2010, Naning

  24. Exclusive pppXp(X) Offers a novel possibility to test QCD Closely related to exclusive Higgs production and provides an excellent test of the theoretical predictions for Higgs production. • Calculations for exclusive Higgs boson production cover a range of over 2 orders of magnitude using different models. • QCD calculation of both diagrams is similar. V.A. Khoze et al., EPJC 38, 475 (2005) Dominant diagram for central exclusive production The primary process is gg→γγ through quark loops, with a screening gluon to cancel the exchanged color. LHEP2010, Naning

  25. CDF result: PRL 99, 242002( 2007) CDF vs. CMSexpected result 7TeV pp collision@CMS ∫L = 300pb-1 (1year) • L = 1031cm-2s-1 σ(2γ, Et>4.5Gev, |η|<3) = 210fb ε = εexeεtriggerεrecoεexe_signal = 0.023 • εexe = 0.3 • εtrigger = 0.22 • εreco = 0.660 • εexe_signal = 1 N = ∫L×σ×ε = 3 (maybe more by a factor of 5-10) 2 candidate events are observed. Event A and B are most likely to arise from γγ production while Event C from π0π0 production. An upper limit on the cross section of di-photon production is set at 410 fb with 95% confidence level. If 2 of the 3 candidates are γγ events, then σ( ) = 90fb for Et(γ)>5GeV, |Eta(γ)|<1 LHEP2010, Naning

  26. LeadingCaloTower Energy unpaired events: events with only one bunch, no collision at all Non-interaction events:zerobias events with zero track Interaction events: zerobias events with more than one track Threshold: 99% position of the distribution of unpaired events (similar to signal) Exclusivity: no extra (dR>0.3 with the two photons) caloTowers with energy above threshold in all these 6 sub-detectors(EB/EE/HB/HE/HF+/HF-) LHEP2010, Naning

  27. 99% threshold vs runNumber Unpaired events(black histogram) are used to calculate the 99% noise threshold. LHEP2010, Naning

  28. Exclusive pppXp(Xee) Exclusive dielectron process is something like pp  pXp, where X is an electrons pair. Such process can be used to: • Measure the integrated luminosity. • Study lepton reconstruction and identification. • Provide control sample for other processes. • Search for physics beyond the standard model. LHEP2010, Naning

  29. Electron reconstruction • Exclusive di-electron process is: • Searching channel for new physics • Novel test to QCD • Closely related to exclusive Higgs production • Using Tag and Probe method for the electron reco efficiency LHEP2010, Naning

  30. Zero-bias study Exclusive dielectron process requires an “empty” event except for two electrons. Since there are always noise in calorimeters, a threshold is needed for discriminating exclusivity. The threshold for each calorimeter can be got by compare non-interacting events with interacting event. LHEP2010, Naning

  31. ttbar cross section Reconstructed Top mass LHEP2010, Naning

  32. C-FJetsassociate production Parton show models: DGLAP , BFKL and CCFM Large discrepancy shows between PYTHIA and CASCADE First study on jet including both forward and central region A cross check for inclusive forward jet cross section Also important for VBF Higgs study LHEP2010, Naning

  33. C-FJetspreliminary result Total systematic about 60% Jet Energy Scale dominating Integrated luminosity 5nb-1 LHEP2010, Naning

  34. Software Work • HCAL Noise Monitoring • RPC reconstruction software update • MPGD Trigger development LHEP2010, Naning

  35. HCAL Noise Monitoring Aim: • to provide HCAL noise information for Hcal operating/developing people and related physics group. main work: • Analyze noise and update result to HCAL noise webpage weekly. • http://lhcsrv1.fnal.gov/rocshare/hcalroc/7TeV2010/NoiseTrend_up_to_date/ • http://lhcsrv1.fnal.gov/rocshare/hcalroc/7TeV2010/NoiseTrend_up_to_date/rbxnoise.html • Develop analyzing program and webpage. • Investigate abnormal runs if needed. Next plan: • The noise mon program seems start to pick up collision events, which cause a fake high noise rate. • A rejection for collision is under developing. LHEP2010, Naning

  36. A glance for the Hcal noise webpage LHEP2010, Naning

  37. RPCEfficiency Measurement LHEP2010, Naning

  38. Contribution on RPC Software LHEP2010, Naning

  39. RPCefficiency performance LHEP2010, Naning

  40. μSeed Reconstruction with RPC LHEP2010, Naning

  41. RPCSeedAlgorithms LHEP2010, Naning

  42. RPC Seed Pattern • Survey bending pattern from full Pt range • Fit the relation of Pt and bendingPhi BendingPhi Seed Pt Pt@Ref BendingPhi LHEP2010, Naning

  43. LHEP2010, Naning

  44. Contribute to ME4/2 Construction 在CERN建立清洁间，由中国高能所,俄罗斯,和美国三国派工程师技术员前来参加批量组装，宇宙线测试，电子学部件安装等工作。样机已经在费米实验室启动，定于2011年在CERN启动全面组装工作。 比照第一期，美国将承担探测器全部部件，电子 学部件及工装的经费，中国和俄罗斯承担各自派 出人员的费用和部分机械部件的加工费用。按照 比例，中国应派人员每年2人,共三年完成。研制 和组装技术没有难点，高能所有着成熟的经验。目 前参加这一部分工作，是我们的责任同时也有益于 年轻学生的硬件训练和培养。 LHEP2010, Naning

  45. Trigger Software Upgrade 由于中国组参加了缪子部分探测器的建造和运行工作，这部分触发软件和硬件的升级工作的参加，有利于我们在其中发挥作用，学习较先进的触发系统硬件和软件。 计划派出人员两人年参加L1缪子触发升级软件开发工作。人员费用由国内承担。 LHEP2010, Naning

  46. MPGD Project R&D LHEP2010, Naning

  47. MPGDtrigger simulation LHEP2010, Naning

  48. Summary CMS China Group contributed ~1% hardware (CSC + RPC) and all of them worked well We have selected a list of physics topics and most of them went well. More contribution both on CMS physics analysis and detector upgrade may be expected as we are going to be supported at lest in next 5 years LHEP2010, Naning

  49. THANK YOU！ TeV Physics and LHC Workshop， CCAST

More Related